Primary
The Jaguar Daimler Heritage Trust holds the factory build records and issues Heritage Certificates. It is the first source for production figures, despatch dates and original specification — though see the caution on its published totals.
Jaguar Service Bulletins, 1954 to 1957 record what changed during production and when, by engine and chassis number. They are the reason this archive can say that the lower chain tensioner changed at engine G4431 in September 1955 rather than vaguely "in 1955".
Clubs and registers
The XK Club, the Jaguar Enthusiasts Club, the Jaguar Drivers Club, and XKData, the register of individual cars.
Specialists
Named through the archive where they did the work or supplied the part: SNG Barratt, Guy Broad, Coventry Auto Components, Twyford Moors, SC Parts, Classic Jaguar of Austin Texas, Burlen Fuel Systems, Aldridge Trimming, Chapman and Cliffe, DT Classics, CAS Engineering.
Published references
Jaguar XK DIY Restoration & Maintenance, Bob Exelby, Porter Press International.
Anders Clausager's and Andrew Whyte's production records, which settle several questions this archive currently has to leave open. Both exist only in print.
The primary source for this archive
Bob Exelby's own manuscript, photographs and drawings, covering 2007 to 2026 — roughly 24,000 words, 182 photographs and 538 recorded purchases.